Many automotive gas line, brake line and power steering line applications provide a hostile environment for flexible conduits. These flexible conduits need to be crush resistant, impact or crash resistant, abrasion resistant, shear resistant, vibration resistant, function in an exterior atmosphere at elevated temperatures up to 275.degree. F. and in some applications up to 450.degree. F. and frequently provide noise insulation or isolation. These flexible conduits also need to be corrosion resistant both to hostile exterior weather and atmospheric conditions and to interior chemical attack by power steering fluid, brake fluid, gasoline, methanol fuel, and formic acid, water and other contaminants in gasoline and methanol fuel. Flexible conduits for power steering and brake lines also require great burst strength. Conventional rubber hoses and nylon tubes have serious shortcomings for these automotive fuel, power steering and brake line applications.